Navigation sidebar disappeared in edit mode after upgrade to 7.1.2? (SOLVED)

Navigation (button) sidebar disappeared in edit mode in all themes after upgrade to 7.1.2. It shows up in Preview. How do I get the sidebar in a theme to be available; i.e., showing up alongside page content for editing?

I’ll reply to my own question. The sidebar came back when I “Source List” i the View Menu. Take note RapidWeaver that it is not intuitive to call the Navigation Sidebar a Source List, if you want people to find it easily.